Nightmare Fuel / Angry Birds Toons

• "Egg Sounds" has Red, Chuck, and Matilda visualizing the unhatched chicks as little versions of themselves. This eventually turns into a squabble, resulting in an appropriately hideous, hypothetical hybrid of the three that freaks them out.
• Red's rather dark Imagine Spot in the episode "Slingshot 101", where he imagines the pigs beating up the Blues, taking the eggs and King Pig eating them, complete with terrifying music and Nightmare Faces as pictured above. See it here.
• At the end of "Party Ahoy", King Pig watches as the volcano on the party island erupts and then sinks, with the pigs there still on it (thankfully, it only happens from the distance). You can even hear the pigs screaming as the island sinks. It's safe to say that King Pig dodged a bullet, as he spent the entire episode trying (and failing) to get to that island.
• King Pig's supposed Demonic Possession in "Pig Possessed". Even his minions know something’s not right with the king when he starts coughing after devouring the claw that causes his possession. Granted, it eventually revealed to be him just being choked by the claw, but it doesn't hide the fact how unsettling the atmosphere was.
• The eponymous story that Chronicler Pig reads to King Pig in "Golditrotters". At first, it plays out like the story it was based on, only with an Angry Birds twist, but then there's the ending: After the titular pig wakes up, she is confronted by three beast-like birds who resemble Red, Matilda, and one of the Blues^note they're supposed to represent the Three Bears from the original story, and they look pissed. It gets worse. After a terrified Golditrotters runs to her home, she sees Terence in place of her grandmother^note earlier in the story, the grandmother was portrayed by Professor Pig. Golditrotters screams in terror, and the story just ends there. It's enough to give King Pig nightmares, because earlier in the episode, he wanted to read a book about a vampire.
• Red's Unstoppable Rage in the beginning of "Happy Hippy", wherein he gets so mad that he's destructive and is foaming at the mouth/beak like a rabid dog. It's easily the angriest Red has ever gotten in the entire franchise. And at the end Matilda goes berserk too as Red futilely tries to get her to calm down, with the fact that she was the one trying to calm Red down earlier making her rage even more terrifying. The music playing during the credits ^note and during Red's Unstoppable Rage in the episode doesn't help one bit.
• Chuck's reaction to finding out that the eggs he was trying to rescue were fake at the end of "Eggshaution" is rather disturbing. To be exact, he goes insane and starts repeatedly shouting the word the characters use to refer to the eggs as he pours white paint that the Blues were using for the fake eggs over his head.
• "Stalker", which features King Pig being stalked by one of his own minions. Namely, the pig that works at the hot dog stand begins to follow King Pig everywhere he goes while making what can only be described as a face of disturbing obsession that stares at you no matter what (and with Scare Chords while at it). Of course it makes King Pig so paranoid that he needs his minions to scout for him so he wouldn't run into the stalker... The title card◊ isn't any less creepy, either. Even after he reveals his true intentions - he only wanted to clean up a messy spot that was on King Pig's backside - the nightmare factor does NOT stop because the king messily eats the leftovers on the floor and the stalker makes the face again, now with "Psycho" Strings and a Staggered Zoom.